Emitter and drip irrigation tube

ABSTRACT

An emitter ( 120 ) forms a flow path that runs to a discharge part ( 250 ) from an intake part ( 220 ) for receiving an irrigation liquid in a tube. The flow path includes a flow volume control part ( 240 ) which includes: an end surface ( 243 ) including a concave inclined surface that faces a film ( 300 ) for receiving the pressure of the liquid inside the tube; a hole ( 244 ) that opens at the center of the flow volume control part ( 240 ) and connects to the discharge part ( 250 ); and a groove ( 245 ) crossing the inclined surface and running to the hole ( 244 ). When the film ( 300 ) adheres to the inclined surface as a result of the pressure of the irrigation liquid inside the tube, the flow volume of the irrigation liquid inside the emitter ( 120 ) is controlled so as to be a volume that can pass through the groove ( 245 ).

TECHNICAL FIELD

The present invention relates to an emitter and a trickle irrigationtube including the emitter.

BACKGROUND ART

A trickle irrigation method is known as a method for culturing plants.In the trickle irrigation method, for example, a trickle irrigation tubeis disposed on the soil in which plants are planted, and irrigationliquid such as water and liquid fertilizer is slowly supplied from thetrickle irrigation tube to the soil. The trickle irrigation method canminimize the consumption amount of the irrigation liquid, and has beenincreasingly attracting attention in recent years.

The trickle irrigation tube typically has a tube and an emitter (alsocalled “dripper”). The emitter typically supplies the soil with theirrigation liquid in the tube at a predetermined rate at which theirrigation liquid is dropped to the soil. Emitters which are piercedinto the tube from the outside, and emitters joined to the inner wallsurface of the tube are known.

For example, the latter emitter has a channel including a pressurereduction channel for allowing the liquid having entered the emitterfrom the internal space of the tube toward the through hole of the tubewhile reducing the pressure of the liquid, and a diaphragm partconfigured to change the volume of a portion of the channel where theirrigation liquid having reduced pressure flows in accordance with thepressure of the liquid of the internal space. The emitter is composed ofa member which is joined to the inner wall surface of the tube, a memberwhich is disposed on the member joined to the inner wall surface, and adiaphragm part which is disposed between the two members. The diaphragmpart is composed of an elastic film such as a silicone rubber film (see,for example, PTL 1).

The emitter can suppress variation of the discharge rate of theirrigation liquid regardless of change of the pressure of the liquid inthe internal space of the tube. Therefore, the emitter is advantageousfrom the viewpoint of uniformly growing multiple plants.

CITATION LIST Patent Literature

PTL 1

Japanese Patent Application Laid-Open No. 2010-46094

SUMMARY OF INVENTION Technical Problem

The emitter is formed by assembling three components. In view of this,the emitter may cause assembling error. In particular, the assemblingerror of the diaphragm part may cause variation of the operation of thediaphragm part, and variation of the discharge rate of the irrigationliquid.

In addition, the emitter is typically a molded article of an inexpensiveresin such as polyethylene and polypropylene, and the diaphragm part iscomposed of a more expensive elastic material such as a silicone rubberfilm. The use of components of different materials has a room forimprovement in material cost reduction.

Further, in the case of a trickle irrigation tube, hundreds of emittersare disposed in one tube in some cases. In the case of a long trickleirrigation tube, the supply pressure of liquid to the tube is requiredto be increased, and consequently the liquid discharge rate of theemitter may not be stable. In view of this, control of the dischargerate of the liquid of the emitter in accordance with the pressure of theliquid in the tube is desired.

Furthermore, from the viewpoint of reducing the material cost and themanufacturing cost of the emitter, an emitter which can be manufacturedwith a single inexpensive material and fewer number of components isdesired.

An object of the present invention is to provide an emitter which canstabilize the discharge rate of the irrigation liquid and can furtherreduce the manufacturing cost. In addition, another object of thepresent invention is to provide a trickle irrigation tube having theemitter.

Solution to Problem

An emitter according to an embodiment of the present invention isintended for quantitatively discharging irrigation liquid in a tube froma discharge port communicating between an inside and an outside of thetube, the emitter being configured to be joined to an inner wall surfaceof the tube configured to distribute the irrigation liquid at a positioncorresponding to the discharge port, the emitter including: a watercollecting part for receiving the irrigation liquid in the tube; apressure reduction channel for allowing the irrigation liquid receivedfrom the water collecting part to flow therethrough while reducing apressure of the irrigation liquid; a flow rate control part forcontrolling a flow rate of the irrigation liquid supplied from thepressure reduction channel in accordance with the pressure of theirrigation liquid in the tube; and a discharge part to which theirrigation liquid having a flow rate controlled by the flow rate controlpart, is supplied, the discharge part being to be facing the dischargeport, wherein: the water collecting part opens at a first surface whichis not joined to the tube in the emitter; the flow rate control partincludes: an opening part which opens at the first surface; a filmhaving flexibility and sealing the opening part to block a communicationof a channel on a downstream side relative to the pressure reductionchannel and the inside of the tube; a recessed surface part depressedwith respect to the film and disposed at a position where the recessedsurface part faces the film in the channel on a downstream side relativeto the pressure reduction channel without making contact with the film,but the recessed surface part being capable of making close contact withthe film; a hole opening at the recessed surface part and communicatedwith the discharge part; and a groove formed on the recessed surfacepart and configured to communicate between the hole and the channel onoutside relative to the recessed surface part; and the film makes closecontact with the recessed surface part when the pressure of theirrigation liquid in the tube is equal to or higher than a predeterminedvalue.

In addition, an emitter according to an embodiment of the presentinvention includes: a water collecting part for receiving irrigationliquid in a tube, the water collecting part having a cylindrical shapeto be inserted to the tube from outside of the tube, the tube beingconfigured to distribute the irrigation liquid; a pressure reductionchannel for allowing the irrigation liquid received from the watercollecting part to flow therethrough while reducing a pressure of theirrigation liquid; a flow rate control part for controlling a flow rateof the irrigation liquid supplied from the pressure reduction channel inaccordance with the pressure of the irrigation liquid in the tube; and adischarge part for discharging the irrigation liquid having a flow ratecontrolled by the flow rate control part to outside of the tube,wherein: a flange part is disposed at a base end of the water collectingpart, the base end representing, when one end of the water collectingpart from which the water collecting part is inserted to the tube isdefined as a tip end, the other end of the water collecting part; theflange part is composed of a combination of a first disk part disposedat the base end of the water collecting part and a second disk part onwhich the discharge part is disposed, the flange part including thepressure reduction channel and the flow rate control part; the flow ratecontrol part includes: a film having flexibility and facing a channel ona downstream side relative to the pressure reduction channel; a pressuretransmission part for transmitting the pressure of the irrigation liquidin the tube to a rear surface of the film; a recessed surface partdepressed with respect to the film and disposed at a position where therecessed surface part faces the film in the channel on a downstream siderelative to the pressure reduction channel without making contact withthe film, but the recessed surface part being capable of making closecontact with the film; a hole opening at the recessed surface part andcommunicated with the discharge part; and a groove formed on therecessed surface part and configured to communicate between the hole andthe channel on outside relative to the recessed surface part; and thefilm makes close contact with the recessed surface part when thepressure of the irrigation liquid in the tube is equal to or higher thana predetermined value.

Further, a trickle irrigation tube according to an embodiment of thepresent invention includes: a tube; and at least one emitter, theemitter being the above-mentioned emitter.

Advantageous Effects of Invention

The emitter according to the present invention controls the dischargerate of the irrigation liquid in accordance with the pressure of theirrigation liquid in the trickle irrigation tube, and thus can stabilizethe discharge rate of the irrigation liquid. In addition, since theemitter according to the present invention can be formed with one or twocomponents by injection molding of a resin material, the manufacturingcost can be further reduced in comparison with conventional emitterscomposed of three parts.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic sectional view of a trickle irrigation tubeaccording to Embodiment 1 of the present invention;

FIG. 2A illustrates a top surface, a front surface and a side surface ofan emitter according to Embodiment 1, and FIG. 2B illustrates a bottomsurface, a front surface and a side surface of the emitter;

FIG. 3A is a plan view of the emitter according to Embodiment 1, FIG. 3Bis a front view of the emitter, FIG. 3C is a back view of the emitter,and FIG. 3D is a side view of the emitter;

FIG. 4 is a bottom view of the emitter according to Embodiment 1;

FIG. 5A is a sectional view of the emitter according to Embodiment 1taken along line A-A of FIG. 3A, FIG. 5B is a sectional view of theemitter taken along line B-B of FIG. 3A, and FIG. 5C is a sectional viewof the emitter taken along line C-C of FIG. 4;

FIG. 6A illustrates a top surface, a front surface and a side surface ofthe emitter of Embodiment 1 in the state before the film is joined tothe emitter main body, and FIG. 6B illustrates a bottom surface, a frontsurface and a side surface of the emitter;

FIG. 7A is a plan view of the emitter of Embodiment 1 in the statebefore the film is joined to the emitter main body, and FIG. 7Billustrates a bottom view of the emitter;

FIG. 8A is a sectional view of the emitter of Embodiment 1 taken alongline A-A of FIG. 7A in the state before the film is joined to theemitter main body, and FIG. 8B is a sectional view of the emitter takenalong line B-B of FIG. 7A, and FIG. 8C is a sectional view of theemitter taken along line C-C of FIG. 7B;

FIG. 9A illustrates part A of FIG. 5A in an enlarged manner in the casewhere the pressure of the irrigation liquid in the tube is equal to orhigher than the first pressure value and is lower than the secondpressure value, FIG. 9B illustrates part A of FIG. 5A in an enlargedmanner in the case where the pressure of the irrigation liquid in thetube is equal to or higher than the second pressure value and is lowerthan the third pressure value, and

FIG. 9C illustrates part A of FIG. 5A in an enlarged manner in the casewhere the pressure of the irrigation liquid in the tube is equal to orhigher than the third pressure value;

FIG. 10 is a schematic sectional view of a trickle irrigation tubeaccording to Embodiment 2 of the present invention;

FIG. 11A is a plan view of an emitter according to Embodiment 2, FIG.11B is a front view of the emitter, FIG. 11C is a bottom view of theemitter, and FIG. 11D is a side view of the emitter;

FIG. 12A is a sectional view of the emitter according to Embodiment 2taken along line A-A of FIG. 11A, FIG. 12B is a sectional view of theemitter taken along line B-B of FIG. 11A;

FIG. 13A is a plan view of a first component of Embodiment 2, FIG. 13Bis a front view of the first component, FIG. 13C is a bottom view of thefirst component, and FIG. 13D is a side view of the first component;

FIG. 14A is a sectional view of the first component of Embodiment 2taken along line A-A of FIG. 13A, FIG. 14B is a sectional view of thefirst component taken along line B-B of FIG. 13A;

FIG. 15A is a plan view of a second component of Embodiment 2, FIG. 15Bis a front view of the second component, FIG. 15C is a bottom view ofthe second component, FIG. 15D is a side view of the second component,and FIG. 15E is a sectional view of the second component taken alongline A-A of FIG. 15A;

FIG. 16A schematically illustrates a state of part A of FIG. 12A in thecase where the pressure of the irrigation liquid in the tube is equal toor higher than the first pressure value and is lower than the secondpressure value, FIG. 16B schematically illustrates a state of part A ofFIG. 12A in the case where the pressure of the irrigation liquid in thetube is equal to or higher than the second pressure value and is lowerthan the third pressure value, and FIG. 16C schematically illustrates astate of part A of FIG. 12A in the case where the pressure of theirrigation liquid in the tube is equal to or higher than the thirdpressure value; and

FIG. 17A schematically illustrates a first modification of a dischargepart of the emitter according to Embodiment 2, and FIG. 17Bschematically illustrates a second modification of the discharge part.

DESCRIPTION OF EMBODIMENTS

In the following, embodiments of the present invention are described indetail with reference to the accompanying drawings.

Embodiment 1 Configuration

FIG. 1 is a schematic sectional view of a trickle irrigation tubeaccording to Embodiment 1 of the present invention. Trickle irrigationtube 100 is composed of tube 110 and emitter 120. Tube 110 is made ofpolyethylene, for example. Emitter 120 is disposed at a predeterminedinterval (for example, 200 to 500 mm) in the axial direction of tube110. Each emitter 120 is joined on the inner wall surface of tube 110.Emitter 120 is disposed at a position where emitter 120 covers dischargeport 130 of tube 110. Discharge port 130 is a hole which extends throughthe tube wall of tube 110. The hole diameter of discharge port 130 is,for example, 1.5 mm. It is to be noted that arrow F indicates thedirection of flow of the irrigation liquid in tube 110.

FIG. 2A illustrates a top surface, a front surface and a side surface ofemitter 120, and FIG. 2B illustrates a bottom surface, a front surfaceand a side surface of emitter 120. FIG. 3A is a plan view of emitter120, FIG. 3B is a front view of emitter 120, FIG. 3C is a back view ofemitter 120, FIG. 3D is a side view of emitter 120, and FIG. 4 is abottom view of emitter 120. FIG. 5A is a sectional view of emitter 120taken along line A-A of FIG. 3A, FIG. 5B is a sectional view of emitter120 taken along line B-B of FIG. 3A, and FIG. 5C is a sectional view ofemitter 120 taken along line C-C of FIG. 4. It is to be noted that the Xdirection is the axial direction of tube 110 or the longitudinaldirection of emitter 120, the Y direction is the short (width) directionof emitter 120, and the Z direction is the height direction of emitter120.

As illustrated in FIG. 2A and FIG. 2B, emitter 120 has a rectangularexternal shape. For example, the length of emitter 120 is 30 mm in the Xdirection, 10 mm in the Y direction, and 3 mm in the Z direction.Emitter 120 includes emitter main body 200 to be joined to the innerwall surface of tube 110, and film 300 which is formed integrally withemitter main body 200.

FIG. 6A illustrates a top surface, a front surface and a side surface ofemitter 120 in the state before film 300 is joined to emitter main body200, and FIG. 6B illustrates a bottom surface, a front surface and aside surface of emitter 120. FIG. 7A is a plan view of emitter 120 inthe state before film 300 is joined to emitter main body 200, and FIG.7B is a bottom view of emitter 120. FIG. 8A is a sectional view ofemitter 120 taken along line A-A of FIG. 7A in the state before film 300is joined to emitter main body 200, FIG. 8B is a sectional view ofemitter 120 taken along line B-B of FIG. 7A, and FIG. 8C is a sectionalview of emitter 120 taken along line C-C of FIG. 7B.

As illustrated in FIG. 3B and FIG. 3C, emitter main body 200 includesfirst surface 201 and second surface 202. First surface 201 is onesurface which is joined to film 300 in the Z direction. Second surface202 is the other surface which is joined to the inner wall surface oftube 110 in the Z direction.

As illustrated in FIG. 5A, FIG. 5B and FIG. 5C, emitter main body 200includes filter part 210 formed on first surface 201, water collectingpart 220 which extends through emitter main body 200 in the Z direction,pressure reduction channel 230 formed on second surface 202, flow ratecontrol part 240 which opens at first surface 201, and discharge part250 formed on second surface 202.

As illustrated in FIG. 6A and FIG. 7A, filter part 210 includes firstrecess 211 which is formed on first surface 201 and has a rectangularshape as the shape viewed from the Z direction (hereinafter alsoreferred to as “shape in plan view”), second recess 212 which is formedon first surface 201 and connects first recess 211 and water collectingpart 220 together, a plurality of first protrusion lines 213 which arearranged side by side in the X direction in first recess 211 such thatthe longitudinal direction thereof is aligned with the Y direction, anda plurality of second protrusion lines 214 which are arranged side byside in the Y direction in second recess 212 such that the longitudinaldirection thereof is aligned with the X direction. A gap is formedbetween first protrusion line 213 and the wall surface of first recess211 in the Y direction, and a gap is formed between an end portion ofsecond protrusion line 214 in the X direction and first protrusion line213 adjacent to second protrusion line 214 in the X direction. Thedistance between the bottom surface of first recess 211 and secondrecess 212 to the tip end surface of first protrusion line 213 andsecond protrusion line 214 (the height of first protrusion line 213 andsecond protrusion line 214) is, for example, 0.5 mm

The opening shape of water collecting part 220 at first surface 201 is acircle as illustrated in FIG. 7A. The opening diameter of watercollecting part 220 is equal to the length of second recess 212 in the Ydirection, and is, for example, 5 mm. As illustrated in FIG. 7B, theopening shape of water collecting part 220 at second surface 202 is ashape (bell shape) which is formed with a semicircle of theabove-mentioned circle and a rectangular which has a width of thediameter of the opening and extends in the Y direction from the diameterof the semicircle.

As illustrated in FIG. 6A and FIG. 6B, water collecting part 220includes flow rate adjustment valve 221. Flow rate adjustment valve 221is composed of four flexible opening-closing parts which cover thecircular opening of water collecting part 220. The opening-closing partshas a form in which a substantially himisphere thin dome protruding fromfirst surface 201 side toward second surface 202 side is divided withslits in a cross shape. The opening-closing part has a thickness of, forexample, 0.5 mm, and, normally, the slit has a width of, for example, 0mm

As illustrated in FIG. 4, pressure reduction channel 230 is formed as agroove on second surface 202. Pressure reduction channel 230 has azigzag shape in plan view. In the zigzag shape, substantially triangularprotrusions protruding from the side surface of pressure reductionchannel 230 are alternately disposed along the longitudinal direction ofpressure reduction channel 230. The protrusions are disposed such thatthe tip of each protrusion does not exceed the central axis of pressurereduction channel 230 in plan view. The above-mentioned groove has adepth of, for example, 0.5 mm, and the above-mentioned groove has awidth (W in FIG. 4) of, for example, 0.5 mm

As illustrated in FIG. 4, one end of pressure reduction channel 230 isconnected with water collecting part 220 with linear groove 231 formedon second surface 202, and the other end of pressure reduction channel230 is connected with linear groove 232 formed on second surface 202.Further, groove 232 is connected with flow rate control part 240 withthrough hole 233 which extends through emitter main body 200 from groove232 and opens to first surface 201 as illustrated in FIG. 5B and FIG.5C. Grooves 231 and 232, and through hole 233 have a width (the lengthin the Y direction) of, for example, 1 mm

As illustrated in FIG. 6A, flow rate control part 240 includes recess241, protrusion 242, end surface 243, hole 244 and groove 245.

As illustrated in FIG. 6A, recess 241 is a bottomed recess which isprovided with an opening part at first surface 201 and is connected withthrough hole 233. In plan view, the opening part has a key-hole likeshape composed of a combination of a circle and a rectangular. Therectangular is a recess which is shallow relative to recess 241, and therectangular recess is connected with through hole 233, whereby throughhole 233 and recess 241 are in communication with each other. Thecircular shape of the opening part has a diameter of, for example, 6 mm.When the opening part is sealed with film 300, recess 241 forms a partof a channel of irrigation liquid on the downstream side relative topressure reduction channel 230. The distance from the bottom of recess241 to first surface 201 in the Z direction (the depth of recess 241)is, for example, 2 mm

As illustrated in FIG. 5A and FIG. 5B, protrusion 242 is a substantiallycylindrical thick body which is provided in an upright manner.Protrusion 242 includes, at an end thereof, end surface 243 which isdisposed at a position where end surface 243 does not make contact withfilm 300 when the opening part is sealed.

As illustrated in FIG. 7A, end surface 243 has a circular shape in planview, and the diameter thereof is, for example, 3 mm End surface 243includes outer ring part 2431 which is parallel to the XY plane, andtilted surface 2432 which is tilted to second surface 202 side from theinner periphery edge of outer ring part 2431 toward hole 244 (FIG. 9A).The distance from outer ring part 2431 to film 300 in the Z directionis, for example, 0.25 mm

Tilted surface 2432 is a curved surface which is slightly depressed withrespect to first surface 201 side. Tilted surface 2432 coincides with avirtual curve, which is formed between the opening edges of the openingpart of recess 241 and is in contact with the opening edges in across-section including the central axis of hole 244 of emitter mainbody 200. The virtual curve includes a curve which is defined by film300 when film 300 receives a pressure of the irrigation liquid in tube110 having a value equal to or higher than a predetermined value in theabove-mentioned cross-section (FIG. 9A and FIG. 9C). The curve has acurvature radius R of, for example, 12 mm

As illustrated in FIG. 5A, hole 244 opens at a center of end surface243, extends through protrusion 242, and opens at recess 246 formed onsecond surface 202. That is, hole 244 communicates between recess 241and recess 246. The hole diameter of hole 244 on end surface 243 sideis, for example, 1 mm. The opening on end surface 243 side of hole 244is smaller than that of the opening on recess 246 side. That is, hole244 is a tapered hole whose diameter gradually increases from endsurface 243 side toward recess 246 side in the Z direction.

In plan view, recess 246 has a key-hole like shape composed of acombination of a circle with the opening of hole 244 at a center portionthereof and a rectangular having a width smaller than the diameter ofthe circle as illustrated in FIG. 4.

As illustrated in FIG. 6A, groove 245 is a groove extending from theouter peripheral edge of end surface 243 to hole 244. That is, groove245 communicates between recess 241 and hole 244. One or more grooves245 may be provided. For example, groove 245 has a width of 2 mm, and adepth of 0.05 mm

As illustrated in FIG. 2B and FIG. 4, discharge part 250 is formed onsecond surface 202 as a recess which is continuous to recess 246 in theX direction and is deep relative to recess 246. In plan view, dischargepart 250 has a rectangular shape. At the connecting part of recess 246and the discharge part, the length of discharge part 250 is greater thanthat of recess 246 in the Y direction.

As illustrated in FIG. 4, slender protrusion line 251 is disposed alongthe Y direction in discharge part 250. As illustrated in FIG. 5A,protrusion line 251 protrudes to second surface 202 from the bottom ofthe recess forming discharge part 250. As illustrated in FIG. 4, in theX direction, protrusion line 251 is disposed at a position away fromrecess 246, and, in the Y direction, the length of protrusion line 251is smaller than that of discharge part 250 and is substantially equal tothat of recess 246 at the connecting part. As described, as viewed fromdischarge part 250 side along the X direction, protrusion line 251 isdisposed at a position where protrusion 251 overlaps recess 246.

As illustrated in FIG. 7A and FIG. 7B, film 300 is disposed integrallywith emitter main body 200 through hinge part 301. Hinge part 301 isdisposed at an edge of first surface 201 of emitter main body 200 in theY direction. For example, hinge part 301 is a portion having a thicknessequal to that of film 300 and a width of 0.5 mm, and is formedintegrally with emitter main body 200 and film 300.

As illustrated in FIG. 7A and FIG. 7B, film 300 further includesrectangular opening part 302 at a position corresponding to first recess211 of filter part 210 in the state where film 300 covers first surface201. For example, the thickness of film 300 may be determined by acomputer simulation or an experiment using a trial product or the likeon the basis of the deformation amount under a pressure described later,and may be, for example, 0.15 mm

Each of emitter main body 200 and film 300 is molded with one materialhaving flexibility such as polypropylene, for example. Examples of thematerial include resin and rubber, and examples of the resin includepolyethylene and silicone. The flexibility of emitter 120 and film 300can be adjusted with use of elastic resin materials, and for example,can be adjusted by the type of an elastic resin, the mixing ratio of anelastic resin material to a hard resin material, and the like. Emitter120 can be manufactured as an integrally molded member by injectionmolding, for example.

(Operation)

Film 300 turns about hinge part 301, and is closely joined on firstsurface 201 of emitter main body 200. For example, the joining isperformed by welding of a resin material of emitter main body 200 orfilm 300, by bonding using an adhesive agent, by pressure bonding offilm 300 to emitter main body 200 or the like. When film 300 is joinedto first surface 201, a channel extending from filter part 210 to watercollecting part 220 is formed, and recess 241 is liquid-tightly sealedwith film 300.

Second surface 202 is joined to the inner wall surface of tube 110. Thejoining is performed by welding of the resin material of emitter mainbody 200 or tube 110, by bonding using adhesive agent, by pressurebonding of emitter main body 200 to tube 110, or the like. When emitter120 is joined to tube 110, water collecting part 220, pressure reductionchannel 230, flow rate control part 240 and discharge part 250 areconfigured to exhibit their desired functions. Normally, emitter 120 isjoined to the inner periphery wall of tube 110 before discharge port 130is formed, and thereafter, discharge port 130 is formed at a positioncorresponding to discharge part 250 of tube 110. Alternatively, emitter120 may be joined to the inner wall surface of tube 110 such thatemitter 120 is located at the position of preliminarily provideddischarge port 130.

Next, discharge of irrigation liquid by emitter 120 is described. FIG.9A illustrates part A of FIG. 5A in an enlarged manner in the case wherethe pressure of the irrigation liquid in tube 110 is equal to or higherthan a first pressure value and lower than a second pressure value. FIG.9B illustrates part A of FIG. 5A in an enlarged manner in the case wherethe pressure of the irrigation liquid in tube 110 is equal to or higherthan the second pressure value and lower than a third pressure value.FIG. 9C illustrates part A of FIG. 5A in an enlarged manner in the casewhere the pressure of the irrigation liquid in tube 110 is equal to orhigher than the third pressure value.

Supply of irrigation liquid to trickle irrigation tube 100 is performedin a range where the pressure of the irrigation liquid does not exceed0.1 MPa for the purpose of preventing damaging of tube 110 and emitter120. When irrigation liquid is supplied into tube 110, the irrigationliquid reaches second recess 212 covered with film 300 in the Zdirection through a gap between first recess 211 and first protrusionline 213 of filter part 210 and reaches water collecting part 220through a gap between second recess 212 and second protrusion line 214.Filter part 210 prevents intrusion of float in the irrigation liquidhaving a size greater than the gap.

When the pressure of the irrigation liquid in tube 110 is equal to orhigher than the first pressure value (for example, 0.005 MPa), flow rateadjustment valve 221 is pushed to second surface 202 side, and the slitof flow rate adjustment valve 221 is expanded. In this manner, theirrigation liquid reaching water collecting part 220 is received byemitter main body 200 from water collecting part 220. Flow rateadjustment valve 221 suppresses inflow of the irrigation liquid toemitter main body 200 when the pressure of the irrigation liquid islower than the first pressure. Thus, high-pressure supply of theirrigation liquid to tube 110 can be achieved, and therefore theconfiguration where emitter 120 has flow rate adjustment valve 221 isfavorable for forming trickle irrigation tube 100 having a greaterlength, for example.

The irrigation liquid received from water collecting part 220 issupplied to pressure reduction channel 230 through groove 231. Thepressure of the irrigation liquid flowing through pressure reductionchannel 230 is reduced as a result of pressure reduction caused by theshape (zigzag shape) in plan view of reduction channel 230. In addition,floats in the irrigation liquid are entangled in the turbulent flowgenerated between the protrusions of pressure reduction channel 230 andare retained in pressure reduction channel 230. In this manner, thefloats are further removed from the irrigation liquid by pressurereduction channel 230.

The irrigation liquid having passed through pressure reduction channel230 in which the pressure is reduced and the floats are removed issupplied into recess 241 of flow rate control part 240 through groove232 and hole 233. When recess 241 is filled with the irrigation liquid,the irrigation liquid is supplied to hole 244 of protrusion 242 througha gap between film 300 and end surface 243 as illustrated in FIG. 9A.

The irrigation liquid having passed through hole 244 reaches recess 246and discharge part 250, and is discharged out of tube 110 throughdischarge port 130 which opens to discharge part 250.

While foreign matters of soil or the like may enter discharge part 250from discharge port 130, intrusion of the foreign matters to recess 246is blocked by protrusion lines 251 of discharge part 250.

As the pressure of the irrigation liquid in tube 110 increases, the flowrate of the irrigation liquid flowing into emitter main body 200 fromwater collecting part 220 increases, and the discharge rate of theirrigation liquid from discharge port 130 increases.

When the pressure of the irrigation liquid in tube 110 is equal to orhigher than the second pressure value (for example, 0.02 MPa), film 300pushed by the irrigation liquid in tube 110 is deflected as illustratedin FIG. 9B. Consequently, the distance between film 300 and end surface243 at flow rate control part 240 is reduced. For example, the distancebetween end surface 243 and film 300 is changed to 0.15 mm Thus, theamount of the irrigation liquid which passes through flow rate controlpart 240 is reduced, and the increase of the discharge rate of theirrigation liquid from discharge port 130 is suppressed.

When the pressure of the irrigation liquid in tube 110 is equal to orhigher than the third pressure value (for example, 0.05 MPa), film 300pushed by the irrigation liquid in tube 110 is further deflected, and isbrought into close contact with end surface 243 (tilted surface 2432) ofprotrusion 242 as illustrated in FIG. 9C. In this manner, film 300functions as a valve element for sealing a hole which is a channel ofthe irrigation liquid under high pressure, and end surface 243 functionsas a valve seat of the valve element. Meanwhile, since groove 245 is notsealed even when film 300 makes close contact with end surface 243, theirrigation liquid supplied to recess 241 is supplied from recess 241 tohole 244 through groove 245. Consequently, the amount of the irrigationliquid which passes through flow rate control part 240 is restricted toa flow rate which can pass through groove 245, and the discharge rate ofthe irrigation liquid from discharge port 130 becomes substantiallyconstant. In this manner, emitter 120 quantitatively discharges theirrigation liquid from tube 110 supplied with the irrigation liquid.

(Effect)

As described above, emitter 120 includes water collecting part 220 forreceiving the irrigation liquid in tube 110, pressure reduction channel230 for allowing the irrigation liquid received from water collectingpart 220 to flow therethrough while reducing the pressure of theirrigation liquid, flow rate control part 240 for controlling the flowrate of the irrigation liquid supplied from pressure reduction channel230 in accordance with the pressure of the irrigation liquid in tube110, and discharge part 250 to which the irrigation liquid having a flowrate controlled by flow rate control part 240 supplied, discharge part250 facing discharge port 130. Water collecting part 220 opens at firstsurface 201 of emitter main body 200. Flow rate control part 240includes an opening part which opens at first surface 201, film 300having flexibility which seals the opening part and blocks communicationbetween a channel on the downstream side relative to pressure reductionchannel 23 and the inside of tube 110, a recessed surface part (tiltedsurface 2432) depressed with respect to film 300 and disposed at achannel on a downstream side relative to pressure reduction channel 230such that the recessed surface part faces film 300 without makingcontact with film 300, but the recessed surface part being capable ofmaking close contact with film 300; hole 244 opening at the recessedsurface part and communicated with discharge part 250, and groove 245formed on the recessed surface part and configured to communicatebetween hole 244 and the channel on outside relative to the recessedsurface part. When emitter 120 is disposed to the inner wall surface oftube 110 at a position corresponding to discharge port 130 of tube 110,trickle irrigation tube 100 is formed. Film 300 starts to deflect whenthe pressure of the irrigation liquid in tube 110 is equal to or higherthan the above-mentioned second pressure value, and film 300 makes closecontact with the recessed surface part when the pressure is equal to orhigher than the third pressure value. Therefore, emitter 120 dischargesthe irrigation liquid such that the amount of the liquid is limited tothe amount which passes through groove 245 even when the pressure of theirrigation liquid in tube 110 increases. In this manner, emitter 120quantitatively discharges the irrigation liquid in tube 110 fromdischarge port 130 in accordance with the pressure of the irrigationliquid in tube 110, and thus can stabilize the discharge rate of theirrigation liquid.

Further, since the above-described components of emitter 120 arecomposed of a recess or a through hole formed on first surface 201 orsecond surface 202 of emitter main body 200, emitter main body 200 canbe integrally produced by injection molding. Therefore, emitter 120 canfurther reduce manufacturing cost in comparison with conventionalemitters composed of three parts.

In addition, with the configuration in which emitter 120 is molded withone material having flexibility and film 300 is integrally molded as apart of emitter 120 such that film 300 can close recess 241, both ofemitter main body 200 and film 300 can be molded as one component byinjection molding, and consequently manufacturing error of the joiningposition of film 300 can be prevented, which is further favorable fromthe standpoint of further reducing manufacturing cost, for example.

In addition, with the configuration in which water collecting part 220further includes water flow rate adjustment valve 221 configured toexpand the irrigation liquid channel at collecting part 220 inaccordance with the increase of the pressure of the irrigation liquid intube 110, the irrigation liquid can be supplied to tube 110 with ahigher pressure, which is further favorable from the viewpoint offorming trickle irrigation tube 100 having a greater length.

(Modification)

In trickle irrigation tube 100, the above-described configurations maybe partially changed, or other configurations may be additionallyprovided as long as the above-described effect is achieved.

For example, tube 110 may be a seamless tube, or a tube composed ofslender sheet(s) joined together along the longitudinal direction.

In addition, discharge port 130 may be a gap formed at theabove-mentioned joining part of the sheet(s) so as to communicatebetween the inside and the outside of tube 110, or a pipe sandwiched bythe sheets at the joining part. Further, the shape of the discharge portin the axial direction may not be a straight line shape. Examples of thetube having the discharge port include a tube in which a depressionhaving a desired shape and serving as a channel is formed on the surfaceof the above-mentioned sheet(s), and a discharge port composed of thechannel is formed at the joining part when the sheets are joinedtogether.

While water collecting part 220 is located at a position on the upstreamside in the flow direction of the irrigation liquid in tube 110, watercollecting part 220 may be located at a position on the downstream side.In addition, the orientations of a plurality of emitters in one tube 110may be identical to each other or different from each other.

In addition, the resin material of emitter main body 200 and the resinmaterial of film 300 may be identical to each other or different fromeach other.

While emitter main body 200 is integrally by injection molding of resin,emitter main body 200 may be composed of two components of a firstsurface 201 side component and a second surface 202 side component. Inthis case, the first surface 201 side component is integrally moldedwith film 300. With the configuration in which emitter main body 200 iscomposed of the two components, a channel such as a pressure reductionchannel can be disposed inside emitter main body 200. It is to be notedthat the two components may be integrally molded through a hinge part.

In addition, pressure reduction channel 230 may be a groove on firstsurface 201 which is covered with film 300 in emitter main body 200.

While the recessed surface part is tilted surface 2432 in the presentembodiment, other suitable configurations may also be adopted as long asit can make close contact with film 300 at a position around hole 244.For example, the recessed surface part may be a planer part located at aposition closer to second surface 202 side than first surface 201 inflow rate control part 240.

While second surface 202 is a planer surface in Embodiment 1, secondsurface 202 may also be a curved surface extending along the inner wallof tube 110 (for example, a surface formed of the arc of the internaldiameter of tube 110 in YZ plane).

Embodiment 2

Now Embodiment 2 of the present invention is described.

(Configuration)

FIG. 10 is a schematic sectional view of trickle irrigation tube 500according to Embodiment 2 of the present invention. Trickle irrigationtube 500 is composed of tube 110 and emitter 620. The configuration oftube 110 is identical to that of the above-described Embodiment 1.

FIG. 11A is a plan view of emitter 620, FIG. 11B is a front view ofemitter 620, FIG. 11C is a bottom view of emitter 620, and FIG. 11D is aside view of emitter 620. In addition, FIG. 12A is a sectional view ofemitter 620 taken along line A-A of FIG. 11A, and FIG. 12B is asectional view of emitter 620 taken along line B-B of FIG. 11A.

As illustrated in FIG. 11B and FIG. 11C, emitter 620 includes watercollecting part 720, pressure transfer pipe 725, flange part 730 anddischarge part 740. Here, the Z direction is a direction along the axisof water collecting part 720, and includes a direction in which emitter620 is inserted to tube 110. The X direction is one direction orthogonalto the Z direction, and the Y direction is a direction orthogonal toboth of the Z direction and the X direction.

The shape viewed along the Z direction (shape in plan view) of flangepart 730 is a circular shape. Flange part 730 has an outer diameter of,for example, 16 mm. As illustrated in FIG. 11A and FIG. 11B, watercollecting part 720 is disposed at a center of flange part 730 in planview, and pressure transfer pipe 725 and discharge part 740 are disposedat positions shifted in the X direction from a center of flange part 730as illustrated in FIG. 11B, FIG. 11C and FIG. 11D.

Flange part 730 is composed of a combination of first disk part 731 onwater collecting part 720 and pressure transfer pipe 725 side and seconddisk part 732 on discharge part 740 side. Water collecting part 720 andpressure transfer pipe 725 are formed integrally with first disk part731, and discharge part 740 is formed integrally with second disk part732. Hereinafter, the integrally molded member of water collecting part720, pressure transfer pipe 725 and first disk part 731 is also referredto as “first component,” and the integrally molded member of dischargepart 740 and second disk part 732 is also referred to as “secondcomponent.”

As illustrated in FIG. 12A and FIG. 12B, water collecting part 720 is acylindrical member uprightly provided on first surface 7311 of firstdisk part 731. Barb 721 is formed at an end portion of water collectingpart 720. Barb 721 is composed of large diameter part 7211 which expandsfrom the outer peripheral surface of water collecting part 720 along theXY plane, and tapered surface 7212 whose outer diameter graduallydecreases from large diameter part 7211 toward an end of watercollecting part 720. For example, large diameter part 7211 has an outerdiameter of 3.2 mm, and the end of tapered surface 7212 has an outerdiameter of 2.6 mm

As with water collecting part 720, pressure transfer pipe 725 is acylindrical member uprightly provided on first surface 7311 of firstdisk part 731 as illustrated in FIG. 12A and FIG. 12B. Barb 726 isformed at an end portion of pressure transfer pipe 725. Barb 726 iscomposed of large diameter part 7261 which expands from the outerperipheral surface of pressure transfer pipe 725 along the XY plane, andtapered surface 7262 whose outer diameter gradually decreases from largediameter part 7261 toward an end of pressure transfer pipe 725. Forexample, large diameter part 7261 has an outer diameter of 4 mm, and theend of tapered surface 7262 has an outer diameter of 3.3 mm

FIG. 13A is a plan view of the first component, FIG. 13B is a front viewof the first component, FIG. 13C is a bottom view of the firstcomponent, and FIG. 13D is a side view of the first component. Inaddition, FIG. 14A is a sectional view of the first component takenalong line A-A of FIG. 13A, and FIG. 14B is a sectional view of thefirst component taken along line B-B of FIG. 13A.

As illustrated in FIG. 13A and FIG. 13C, first disk part 731 includesrecess 7313 on first surface 7311 side, and protrusion line 7314, firstrecess 7315, pressure reduction channel 750, channel 760, second recess7316 and flow rate adjustment valve 780 on second surface 7312 sidewhich is an opposite side of first surface 7311 in the Z direction.

As illustrated in FIG. 14A, recess 7313 is a recess formed on firstsurface 7311. In plan view, recess 7313 has a circular shape asillustrated in FIG. 13A. The bottom of recess 7313 composes film 770described later. Recess 7313 has a diameter of, for example, 3 mm, andrecess 7313 has a depth from first surface 7311 of, for example, 0.65 mmPressure transfer pipe 725 is in communication with recess 7313.

As illustrated in FIG. 13C, protrusion line 7314 is disposed at theperipheral portion of second surface 7312, and as illustrated in FIG.14A and FIG. 14B, protrusion line 7314 protrudes from second surface7312. The height of protrusion line 7314 from second surface 7312 is,for example, 1 mm

As illustrated in FIG. 13C, first recess 7315 is formed at a center ofsecond surface 7312. In plan view, first recess 7315 has a circularshape. First recess 7315 is in communication with the inside of watercollecting part 720, and the diameter of first recess 7315 is slightlylarger than the internal diameter of water collecting part 720. Thedepth of first recess 7315 from second surface 7312 is, for example, 0.5mm

As illustrated in FIG. 14B, pressure reduction channel 750 is a portionformed as a groove on second surface 7312. As illustrated in FIG. 13C,pressure reduction channel 750 is connected with first recess 7315, andextends toward the peripheral portion of second surface 7312 along theradial direction of second surface 7312. In plan view, pressurereduction channel 750 has a zigzag shape as with the above-describedpressure reduction channel 230, and pressure reduction channel 750 has awidth (W in FIG. 13C) of, for example, 0.45 mm

As illustrated in FIG. 14A and FIG. 14B, channel 760 is formed as agroove on second surface 7312. As illustrated in FIG. 13C, at theperipheral portion of second surface 7312, the base end of channel 760is connected with pressure reduction channel 750, and channel 760extends along the extending direction of pressure reduction channel 750.While an end of channel 760 is extended to a region near first recess7315, the end portion of channel 760 and first recess 7315 are not incommunication with each other.

As illustrated in FIG. 14A, second recess 7316 is a recess formed onsecond surface 7312. As illustrated in FIG. 13C, second recess 7316 isadjacent to an end portion of channel 760, and has a rectangular shapein plan view. In the Z direction, second recess 7316 overlaps recess7313 on first surface 7311 side, and this overlapping part is thin film770. Accordingly, film 770 has a circular shape in plan view. The depthof second recess 7316 from second surface 7312 is, for example, 0.2 mm,and the thickness of film 770 is, for example, 0.15 mm. The thickness offilm 770 is determined by a computer simulation or an experiment using atrial product or the like on the basis of the deformation amount under apressure described later, for example.

As with the above-described flow rate adjustment valve 221, flow rateadjustment valve 780 is composed of four opening-closing parts. Asillustrated in FIG. 13C, FIG. 14A and FIG. 14B, the opening-closing parthas a form similar to the form in which a substantially himisphere thindome protruding from the inner base end of water collecting part 720toward first recess 7315 is divided with slits in a cross shape. Theslit has a width of, for example, 0 mm, and the opening-closing part hasa thickness of, for example, 0.2 mm

As illustrated in FIG. 12A, discharge part 740 is a cylindrical memberuprightly provided on first surface 7321 of second disk part 732. Aswith water collecting part 720, barb 741 is formed at an end portion ofdischarge part 740. Barb 741 is composed of large diameter part 7411which expands from the outer peripheral surface of discharge part 740along XY plane, and tapered surface 7412 whose outer diameter graduallydecreases from large diameter part 7411 toward an end of discharge part740. For example, large diameter part 7411 has an outer diameter of 5mm, and the end of tapered surface 7412 has an outer diameter of 4 mm

FIG. 15A is a plan view of the second component, FIG. 15B is a frontview of the second component, FIG. 15C is a bottom view of the secondcomponent, FIG. 15D is a side view of the second component, and FIG. 15Eis a sectional view of the second component taken along line A-A of FIG.15A. Second disk part 732 includes recessed line 7324, recessed surfacepart 810, hole 820 and groove 830.

As illustrated in FIG. 15A, recessed line 7324 is disposed at theperipheral portion of second surface 7322 which is an opposite side offirst surface 7321 in the Z direction, and, as illustrated in FIG. 15Band FIG. 15D, is depressed from second surface 7322. The depth ofrecessed line 7324 from second surface 7322 is, for example, 1 mm

As illustrated in FIG. 12A, recessed surface part 810 is a recess formedat a position facing film 770 in second surface 7322. In plan view,recessed surface part 810 has a circular shape as illustrated in FIG.15A. Recessed surface part 810 has a diameter of, for example, 1.8 mmRecessed surface part 810 is formed with a curved surface slightlydepressed from second surface 7322, and is formed such that film 770makes close contact with at least a part surrounding hole 820 ofrecessed surface part 810 when film 770 is deflected under a pressure ofthe irrigation liquid having a value equal to or higher than apredetermined value in pressure transfer pipe 725 in pressure transferpipe 725.

As illustrated in FIG. 15A, hole 820 opens at a center portion ofrecessed surface part 810. The opening of hole 820 on recessed surfacepart 810 side has a circular shape. As illustrated in FIG. 15E, hole 820penetrates second disk part 732 along the Z direction, and is incommunication with the inside of discharge part 740. The opening of hole820 on recessed surface part 810 side has a diameter of, for example, 1mm, and is smaller than the opening on discharge part 740 side. That is,hole 820 is a tapered hole whose diameter gradually increases fromrecessed surface part 810 side toward discharge part 740 side along theZ direction.

As illustrated in FIG. 15E, groove 830 is formed on second surface 7322including recessed surface part 810 so as to cross recessed surface part810 along the radial direction thereof. In emitter 620, groove 830communicates between channel 760 and hole 820 as illustrated in FIG.12A. Groove 830 has a width of, for example, 0.2 mm, and has a depthfrom second surface 7322 of, for example, 0.05 mm

As with emitter main body 200 of Embodiment 1, each of the firstcomponent and second component is integrally molded by injection moldingusing one resin material having flexibility (for example,polypropylene). It is to be noted that examples of the material of thefirst component and second component include resin and rubber, andexamples of the resin include polyethylene and silicone. The flexibilityof the material is properly adjusted by the type of the resin material,mixture of two or more resin materials or the like in accordance withthe flexibility required for film 770.

(Operation)

Protrusion line 7314 of first disk part 731 is fitted with recessed line7324 of second disk part 732, whereby second surface 7312 of first diskpart 731 and second surface 7322 of second disk part 732 make closecontact with each other and thus emitter 620 is formed as illustrated inFIG. 12B. Further, second surfaces 7312 and 7322 may be joined bywelding of a resin material, by bonding using an adhesive agent, bypressure bonding of one of them to the other or the like.

As illustrated in FIG. 10, emitter 620 is attached to tube 110 byinserting water collecting part 720 and pressure transfer pipe 725 tothe tube wall of tube 110. Emitter 620 may be attached to tube 110 bypenetrating the tube wall of tube 110 with water collecting part 720 andpressure transfer pipe 725, or by inserting water collecting part 720and pressure transfer pipe 725 to an opening part for insertion which ispreliminarily formed on the tube wall of tube 110. The formerconfiguration is favorable for freely attaching emitter 620 to tube 110,and the latter configuration is favorable for preventing leakage ofirrigation liquid from tube 110. Since water collecting part 720 andpressure transfer pipe 725 each has a barb at an end portion thereof,dropping of emitter 620 from tube 110 is prevented.

Next, discharge of irrigation liquid by emitter 620 is described. FIG.16A schematically illustrates a state of part A of FIG. 12A in the casewhere the pressure of the irrigation liquid in tube 110 is equal to orhigher than the first pressure value and is lower than the secondpressure value, FIG. 16B schematically illustrates a state of part A ofFIG. 12A in the case where the pressure of the irrigation liquid in tube110 is equal to or higher than the second pressure value and is lowerthan the third pressure value, and FIG. 16C schematically illustrates astate of part A of FIG. 12A in the case where the pressure of theirrigation liquid in tube 110 is equal to or higher than the thirdpressure value.

Supply of irrigation liquid to trickle irrigation tube 500 is performedin a range where the pressure of the irrigation liquid does not exceed0.1 MPa for the purpose of preventing damaging of tube 110 and emitter620. When the irrigation liquid is supplied into tube 110, theirrigation liquid reaches flow rate adjustment valve 780 through watercollecting part 720, and pressure transfer pipe 725 is filled with theirrigation liquid (FIG. 12B).

When the pressure of the irrigation liquid in tube 110 is equal to orhigher than the first pressure value (for example, 0.005 MPa), flow rateadjustment valve 780 is pushed to first recess 7315 side, and the slitof flow rate adjustment valve 780 is expanded. In this manner, theirrigation liquid reaching flow rate adjustment valve 780 is supplied topressure reduction channel 750 via adjustment valve 780 and throughfirst recess 7315 (FIG. 12B). Thus, flow rate adjustment valve 780suppresses distribution of the irrigation liquid in emitter 620 when thepressure of the irrigation liquid is lower than the first pressure.Consequently, the irrigation liquid can be supplied to tube 110 with ahigh pressure, and therefore the configuration in which emitter 620 hasflow rate adjustment valve 780 is favorable for forming trickleirrigation tube 500 having a greater length, for example.

The pressure of the irrigation liquid flowing through pressure reductionchannel 750 is reduced as a result of pressure reduction caused by theshape of reduction channel 750 in plan view (zigzag shape). In addition,floats in the irrigation liquid are entangled in the turbulent flowgenerated between the above-mentioned protrusions of pressure reductionchannel 750, and retained in pressure reduction channel 750. In thismanner, floats are further removed from irrigation liquid by pressurereduction channel 750.

The irrigation liquid having passed through pressure reduction channel750 in which the pressure is reduced and the floats are removed issupplied to second recess 7316 (the space sandwiched by film 770 andrecessed surface part 810) through channel 760 and passes through hole820 as illustrated in FIG. 16A. Then, the irrigation liquid isdischarged out of tube 110 through part 740 (FIG. 12A).

As the pressure of the irrigation liquid in tube 110 increases, the flowrate of the irrigation liquid flowing into emitter 620 from watercollecting part 720 increases, and consequently the discharge rate ofthe irrigation liquid from discharge port 740 increases.

When the pressure of the irrigation liquid in tube 110 is equal to orhigher than the second pressure value (for example, 0.02 MPa), film 770is pushed by the irrigation liquid in pressure transfer pipe 725 and isdeflected as illustrated in FIG. 16B. Since no structure which causespressure reduction is provided inside pressure transfer pipe 725, thepressure of the irrigation liquid in pressure transfer pipe 725 issubstantially the same as that of the irrigation liquid in tube 110. Inthis manner, pressure transfer pipe 725 transmits the pressure of theirrigation liquid in tube 110 to the rear surface of film 770. Thus,film 770 is pushed from pressure transfer pipe 725 side by the pressureof the irrigation liquid in the tube, and the distance between film 770and recessed surface part 810 is reduced. For example, the distance ischanged to 0.25 mm to 0.15 mm Consequently, the amount of the irrigationliquid which passes between film 770 and recessed surface part 810 isreduced, and the increase of the discharge rate of the irrigation liquidfrom discharge port 740 is suppressed.

When the pressure of the irrigation liquid in tube 110 is equal to orhigher than the third pressure value (for example, 0.05 MPa), film 770is pushed and further deflected by the irrigation liquid in tube 110 andbrought into close contact with recessed surface part 810 as illustratedin FIG. 16C. In this manner, film 770 functions as a valve element forrestricting the distribution of irrigation liquid, and recessed surfacepart 810 functions as a valve seat. Meanwhile, since groove 830 is notsealed even when film 770 makes close contact with recessed surface part810, the irrigation liquid having passed through channel 760 is suppliedto hole 820 through groove 830. Consequently, the amount of theirrigation liquid which passes through hole 820 is restricted to a flowrate which can pass through groove 830, and the discharge rate of theirrigation liquid from discharge port 740 becomes substantiallyconstant. In this manner, emitter 620 quantitatively discharges theirrigation liquid from tube 110 supplied with the irrigation liquid.

(Effect)

As described, emitter 620 includes: water collecting part 720 forreceiving irrigation liquid in tube 110, water collecting part 720having a cylindrical shape to be inserted to tube 110 from outside oftube 110, tube 110 being configured to distribute irrigation liquid;pressure reduction channel 750 for allowing the irrigation liquidreceived from water collecting part 720 to flow therethrough whilereducing a pressure of the irrigation liquid; a flow rate control partfor controlling a flow rate of the irrigation liquid supplied frompressure reduction channel 750 in accordance with the pressure ofirrigation liquid in tube 110; and discharge part 740 for dischargingfrom tube 110 the irrigation liquid having a flow rate controlled by theflow rate control part to outside of tube 110. When one end of watercollecting part 720 from which water collecting part 720 is inserted totube 110 is defined as a tip end and the other end of water collectingpart 720 is a base end, a flange part is disposed at the base end ofwater collecting part 720. Flange part 730 is composed of a combinationof first disk part 731 disposed at the base end of water collecting part720 and second disk part 732 on which discharge part 740 is disposed,flange part 730 including pressure reduction channel 750 and the flowrate control part. The flow rate control part includes: film 770 havingflexibility disposed to face a channel on a downstream side relative topressure reduction channel 750; a pressure transmission part fortransmitting the pressure of irrigation liquid in tube 110 to a rearsurface of film 770; a recessed surface part 810 depressed with respectto film 770 and disposed at a channel on a downstream side relative topressure reduction channel 750 such that recessed surface part 810 facesfilm 770 without making contact with film 770, recessed surface part 810being capable of making close contact with film 770, and; a hole openingat recessed surface part 810 and communicated with discharge part 740;and groove 830 formed on recessed surface part 810 and configured tocommunicate between the hole and the channel on outside relative torecessed surface part 810. When water collecting part 720 is inserted totube 110, emitter 620 is disposed to tube 110, and trickle irrigationtube 500 is formed. Film 700 starts to deflect when the pressure of theirrigation liquid in tube 110 is equal to or higher than theabove-mentioned second pressure value, and film 700 makes close contactwith the recessed surface part when the pressure is equal to or higherthan the third pressure value. Therefore, emitter 620 discharges theirrigation liquid such that the amount of the liquid is limited to theamount which passes through groove 830 even when the pressure of theirrigation liquid in tube 110 increases. In this manner, emitter 620quantitatively discharges the irrigation liquid in tube 110 fromdischarge port 740 in accordance with the pressure of the irrigationliquid in tube 110, and thus can stabilize the discharge rate of theirrigation liquid.

Further, since the above-described components of emitter 620 arecomposed of a recess or a through hole formed on the first surface orthe second surface of the first component and the second component, eachof the first component and the second component can be integrallyproduced by injection molding. Therefore, emitter 620 can further reducemanufacturing cost in comparison with conventional emitters composed ofthree parts.

In addition, with the configuration in which first disk part 731includes pressure reduction channel 750, pressure transfer pipe 725 andfilm 770 and second disk part 732 includes recessed surface part 810,hole 820 and groove 830, each of the first component and the secondcomponent can be fabricated with a further simplified structure, whichis further favorable from the standpoint of further reducingmanufacturing cost.

Further, as described later in the modification, with the configurationin which first disk part 731 and second disk part 732 are integrallyformed with the same material, emitter 620 can be produced with onecomponent, which is favorable from the standpoint of further reducingmanufacturing cost.

In addition, with the configuration in which water collecting part 720further includes flow rate adjustment valve 780 for expanding thechannel for the irrigation liquid when the pressure of the irrigationliquid in tube 110 is equal to or higher than a predetermined value, theirrigation liquid can be supplied to tube 110 with a higher pressure,which is favorable from the standpoint of forming trickle irrigationtube 500 having a greater length.

(Modification)

In trickle irrigation tube 500, the above-described configurations maybe partially changed, or other configurations may be additionallyprovided as long as the above-described effect is achieved.

For example, discharge part 740 may not have barb 741 as illustrated inFIG. 17A, and may be an opening part which opens at first surface 7321of second disk part 732 as illustrated in FIG. 17B.

In addition, tube 110 may be a seamless tube, a tube composed of slendersheet(s) joined together along the longitudinal direction, or a tubehaving a gap formed at the above-mentioned joining part of the sheets soas to communicate between the inside and the outside of tube 110, or apipe sandwiched by the sheets at the joining part.

In addition, the first component and the second component may beintegrally formed so as to be turnable about a hinge part integrallyformed with the first component and the second component. In this case,the number of components of emitter 620 can be further reduced, that isemitter 620 can be produced with one component.

In addition, emitter 620 may include, in place of pressure transfer pipe725, a part for transmitting to film 770 deflection of film 770 inaccordance with the pressure of the irrigation liquid in tube 110, or, apart capable of directly or indirectly transmitting to the rear surfaceof film 770 the pressure of the irrigation liquid in the tube.

While recessed surface part 810 is a curved surface slightly depressedfrom second surface 7322 in the present embodiment, other suitableconfigurations may also be adopted as long as close contact with film770 around hole 820 is achieved. For example, recessed surface part 810may be a planer part located at a position nearer to first surface 7321side than second surface 7322.

This application is entitled to and claims the benefit of JapanesePatent Application No. 2013-245228 filed on Nov. 27, 2013, thedisclosure each of which including the specification, drawings andabstract is incorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

According to the present invention, an emitter which can dischargeliquid with an appropriate speed by the pressure of the liquid to bedischarged can be easily provided. Accordingly, popularization of theabove-mentioned emitter in technical fields such as trickle irrigationsand endurance tests where long-term discharging is required, and furtherdevelopment of the technical fields can be expected.

REFERENCE SIGNS LIST

-   100, 500 Trickle irrigation tube-   110 Tube-   120, 620 Emitter-   130 Discharge port-   200 Emitter main body-   201, 7311, 7321 First surface-   202, 7312, 7322 Second surface-   210 Filter part-   211, 7315 First recess-   212, 7316 Second recess-   213 First protrusion line-   214 Second protrusion line-   220, 720 Water collecting part-   221, 780 Flow rate adjustment valve-   230, 750 Pressure reduction channel-   231, 232, 245, 830 Groove-   233 Through hole-   240 Flow rate control part-   241, 246, 7313 Recess-   242 Protrusion-   243 End surface-   244, 820 Hole-   250, 740 Discharge part-   251, 7314 Protrusion line-   300, 770 Film-   301 Hinge part-   302 Opening part-   721, 726, 741 Barb-   725 Pressure transfer pipe-   730 Flange part-   731 First disk part-   732 Second disk part-   760 Channel-   810 Recessed surface part-   2431 Outer ring part-   2432 Tilted surface-   7211, 7411, 7261 Large diameter part-   7212, 7412, 7262 Tapered surface-   7324 Recessed line

1. An emitter for quantitatively discharging irrigation liquid in a tubefrom a discharge port communicating between an inside and an outside ofthe tube, the emitter being configured to be joined to an inner wallsurface of the tube configured to distribute the irrigation liquid at aposition corresponding to the discharge port, the emitter comprising: awater collecting part for receiving the irrigation liquid in the tube; apressure reduction channel for allowing the irrigation liquid receivedfrom the water collecting part to flow therethrough while reducing apressure of the irrigation liquid; a flow rate control part forcontrolling a flow rate of the irrigation liquid supplied from thepressure reduction channel in accordance with the pressure of theirrigation liquid in the tube; and a discharge part to which theirrigation liquid, having a flow rate controlled by the flow ratecontrol part, is supplied, the discharge part being to be facing thedischarge port, wherein: the water collecting part opens at a firstsurface which is not joined to the tube in the emitter, the flow ratecontrol part includes: an opening part which opens at the first surface,a film having flexibility and sealing the opening part to block acommunication of a channel on a downstream side relative to the pressurereduction channel and the inside of the tube, a recessed surface partdepressed with respect to the film and disposed at a position where therecessed surface part faces the film in the channel on a downstream siderelative to the pressure reduction channel without making contact withthe film, but the recessed surface part being capable of making closecontact with the film, a hole opening at the recessed surface part andcommunicated with the discharge part, and a groove formed on therecessed surface part and configured to communicate between the hole andthe channel on outside relative to the recessed surface part; and thefilm makes close contact with the recessed surface part when thepressure of the irrigation liquid in the tube is equal to or higher thana predetermined value.
 2. The emitter according to claim 1, wherein: theemitter is molded with one material having flexibility, and the film isintegrally molded as a part of the emitter such that the film is capableof closing the recessed surface part.
 3. The emitter according to claim1 or 2, wherein the water collecting part further includes a flow rateadjustment valve configured to expand a channel of the irrigation liquidwhen the pressure of the irrigation liquid in the tube is equal to orhigher than a predetermined value.
 4. An emitter comprising: a watercollecting part for receiving irrigation liquid in a tube, the watercollecting part having a cylindrical shape to be inserted to the tubefrom outside of the tube, the tube being configured to distribute theirrigation liquid; a pressure reduction channel for allowing theirrigation liquid received from the water collecting part to flowtherethrough while reducing a pressure of the irrigation liquid; a flowrate control part for controlling a flow rate of the irrigation liquidsupplied from the pressure reduction channel in accordance with thepressure of the irrigation liquid in the tube; and a discharge part fordischarging the irrigation liquid having a flow rate controlled by theflow rate control part to outside of the tube, wherein: a flange part isdisposed at a base end of the water collecting part, the base endrepresenting, when one end of the water collecting part from which thewater collecting part is inserted to the tube is defined as a tip end,the other end of the water collecting part, the flange part is composedof a combination of a first disk part disposed at the base end of thewater collecting part and a second disk part on which the discharge partis disposed, the flange part including the pressure reduction channeland the flow rate control part; the flow rate control part includes: afilm having flexibility and facing a channel on a downstream siderelative to the pressure reduction channel, a pressure transmission partfor transmitting the pressure of the irrigation liquid in the tube to arear surface of the film, a recessed surface part depressed with respectto the film and disposed at a position where the recessed surface partfaces the film in the channel on a downstream side relative to thepressure reduction channel without making contact with the film, but therecessed surface part being capable of making close contact with thefilm, a hole opening at the recessed surface part and communicating withthe discharge part; and a groove formed on the recessed surface part andconfigured to communicate between the hole and the channel on outsiderelative to the recessed surface part; and the film makes close contactwith the recessed surface part when the pressure of the irrigationliquid in the tube is equal to or higher than a predetermined value. 5.The emitter according to claim 4, wherein the first disk part includesthe pressure reduction channel, the pressure transmission part and thefilm, and the second disk part includes the recessed surface part, thehole, and the groove.
 6. The emitter according to claim 4, wherein thefirst disk part and the second disk part are integrally formed with asame material.
 7. The emitter according to claim 4, wherein the watercollecting part further includes a flow rate adjustment valve configuredto expand a channel of the irrigation liquid when the pressure of theirrigation liquid in the tube is equal to or higher than a predeterminedvalue.
 8. A trickle irrigation tube comprising: a tube; and at least oneemitter, the emitter being the emitter according to claim 1 disposed onthe tube.
 9. The emitter according to claim 2, wherein the watercollecting part further includes a flow rate adjustment valve configuredto expand a channel of the irrigation liquid when the pressure of theirrigation liquid in the tube is equal to or higher than a predeterminedvalue.
 10. The emitter according to claim 5, wherein the first disk partand the second disk part are integrally formed with a same material. 11.The emitter according to claim 5, wherein the water collecting partfurther includes a flow rate adjustment valve configured to expand achannel of the irrigation liquid when the pressure of the irrigationliquid in the tube is equal to or higher than a predetermined value. 12.The emitter according to claim 6, wherein the water collecting partfurther includes a flow rate adjustment valve configured to expand achannel of the irrigation liquid when the pressure of the irrigationliquid in the tube is equal to or higher than a predetermined value. 13.The emitter according to claim 10, wherein the water collecting partfurther includes a flow rate adjustment valve configured to expand achannel of the irrigation liquid when the pressure of the irrigationliquid in the tube is equal to or higher than a predetermined value. 14.A trickle irrigation tube comprising: a tube; and at least one emitter,the emitter being the emitter according to claim 4 disposed on the tube.